In many areas of the country where irrigation is practiced, earthen levees are provided, which have a high water side and a low water side. By placing a floodgate in an earthen levee, which has a cut therein, in a flow-passing position, water is allowed to flow from the high water side of the levee to the low water side thereof.
Conventional floodgates on the market include steel and fiberglass floodgates which are placed in the cuts in the levee. Steel floodgates, while effective, are very expensive (about $30.00 to $40.00), a lift is needed to install them, they must be repainted yearly to have any significant life, and they rarely last more than 3 to 5 years even if painted. Fiberglass floodgates are susceptible to destruction by animals such as muskrats, and therefore often are not even operative for a full season. It has also been known in the past for individuals to purchase sheets of fabric and nail cypress logs to one end thereof, and use the fabric as a floodgate, however such floodgates rarely last for more than a year due to the deleterious effects of the environment on the fabric.
According to the present invenion, a floodgate is provided that is much less expensive than the steel floodgates -- perhpas being about $4.00 to $5.00 in cost -- yet will last for three to five seasons before it must be replaced. The floodgate according to the present invention comprises a generally rectangular piece of sheet material having a sufficient length to pass from the bottom of one side of the levee, over the crown of the levee, to the bottom of the other side of the levee, and having sufficient width to extend completely across the width of the cut in the levee and a substantial distance on either side of the cut in the levee. In the flow-passing position of the floodgate, the sheet material completely lines the cut in the levee. The floodgate also includes an elongated relatively rigid pole having a length greater than the width of the cut in the levee, and having a cross-sectional area, and a loop formed in the piece of sheet material along one end thereof, generally across the width thereof, the loop having a void area encompassed thereby at least as great as the cross-sectional area of the pole so that the pole may be received by the loop, and so that the pole may be rotated to wrap the sheet material around the pole while the pole is received by the loop. For long life, the sheet material may be nylon coated with plastic (with ultraviolet inhibitor), or polypropylene or polyethylene having ulatraviolet inhibitor incorporated therein. Preferably, about 10% conventional ultraviolet inhibitor is incorporated therein, and the plastic sheet is about 14 to 16 mils thick. In normal usage, the polyethylene sheet will be about 9 feet wide and about 4 or more feet long, not including the loop, and the void area defined by the loop will be about 5.5 square inches, and can accomodate poles of varying cross-sectional shape.
In combination with an earthen levee having a cut therein, the edge of the sheet opposite the loop is buried underground on the high water side of the levee, and the edges of the sheet adjacent the edge opposite the edge of the sheet having the loop are buried along the length thereof up to approximately the crown of the levee, and are free from the crown of the levee toward the low water side of the levee. The levee may have a depression formed in the crown thereof for receipt of the pole with part of the plastic sheet wrapped therearound.
In using the floodgate, when the floodgate is to act to prevent flow of water from the high water side to the low water side, the pole is used to wrap up about half of the length of the sheet, and the pole width sheet wrapped therearound is placed on the crown of the levee. When it is then desired to allow flow through the cut in the levee, the sheet material around the pole is unwrapped, and the pole is placed at the bottom of the low water side of the levee, whereby the sheet deforms to lie in the cut in the levee but allows flow of water from the high water side to the low water side.
It is a primary object of the present invention to provide a long life, simple, inexpensive floodgate for use with earthen levees. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.